To reduce the negotiation time between a wireless access terminal (e.g., a cell phone or other mobile station) and a base station during a call set-up procedure, code division multiple access (CDMA) wireless networks have begun implementing a parameter called the SYNC_ID. The SYNC_ID is a variable length, signature code of the service configuration record (SCR) and the non-negotiable service configuration record (NNSCR) parameters. Without the SYNC_ID parameter, a call set-up procedure could require anywhere from an extra few hundred milliseconds up to several extra seconds.
However, the generation of signature codes is not standardized among base station vendors. Under the latest release of cdma2000 standards, the mobile station is capable of storing at least four SYNC_ID values (or signature codes). Thus, as a mobile station travels through the coverage areas of four base transceiver subsystems, the mobile station stores four different SYNC_ID parameters.
If the mobile station later visits one of the four previously visited base transceiver subsystems, the mobile station may not know which of the four SYNC_ID values to use. Even though the mobile station has stored the SYNC_ID parameter values of all the visited base transceiver subsystems, the mobile station may not able to pick the correct SYNC_ID. Typically, in this situation, the mobile station attempts to guess the correct SYNC_ID parameter, and originates with the selected SYNC_ID parameter. The base station rejects or accepts the SYNC_ID sent by the mobile station, depending on whether that SYNC_ID value is available to the base station.
Under conventional approaches, there is no mechanism in place to allow the mobile station or base station to choose another proposed SYNC_ID. Hence if the mobile station guess is wrong the first time, and the base station rejects the SYNC_ID value, the base station also rejects the call. Thus, the usefulness of the SYNC_ID value feature relies on the mobile station correctly guessing the correct SYNC_ID value. The various failure scenarios involving the SYNC_ID result in longer call set-up time, because if the base station rejects the proposed SYNC_ID, the mobile station must start the process of origination all over again. In sum, the current approach to using the SYNC_ID parameter is problematic.
Therefore, there is a need in the art for improved wireless networks and improved wireless terminals for accessing the wireless networks. In particular, there is a need for CDMA2000 wireless network base stations and wireless mobile stations that use an enhanced SYNC_ID parameter to minimize the number of dropped calls.